Add support to disable hardwrap in wikitext (markdown)

By prepending a wikitext with: <!--NO_HARDWRAPS--> or <!--DISABLE_HARDWRAPS--> (case insensitive) disable the hardwrap option, such that a new line will only become a new line/paragraph when adding 2 whitespaces at the end of the first line, or by using 2 newlines (default markdown spec).

This way we keep hard wraps the default, but allow one to disable hard wraps per wikitext.Later we might introduce an application-wide setting for it.